Image reproduction devices, such as printers, copiers, scanners, facsimile machines, xerographic devices, etc., involve various image reproduction functions, e.g., paper transporting, print head motion, carriage assembly movement, or other tasks, commonly carried out by servo-mechanisms employing dc motors. Various other sub-assemblies, such as registration, inverter, de-curler, and duplex assemblies within a xerographic device are driven by either belts tensioned around a pulley of a dc motor or direct gear to gear engagement to a dc motor.
During the manufacture of paper transport devices, for example, non-visual defects can be difficult to detect on the production line. Internal problems caused by, for instance, bearing drag, incorrect belt tension, roller misalignment, gear binding, and the like, can be difficult to detect and perhaps missed entirely during a quality control check. Manually running paper through a paper transport device and evaluating the results can be time consuming and costly. Problems and defects may be overlooked entirely.
If a paper transport sub-assembly with internal problems ends up as a device component of a larger complex document reproduction system and subsequently fails, the entire system may be down for repair until a technician can diagnose the problem and replace the failing part. Having a document reproduction system down for repair can result in loss of productivity, loss of revenue, and the like, leading to overall customer dissatisfaction with the product. Thus there is a need in this art for methods which enable the diagnosis and detection of sub-assembly performance problems earlier in the manufacturing process.
Outside of the realm of manufacturing, the determination of performance problems for sub-assemblies becomes more important during the operational life of the document reproduction system when wear and contaminants may cause problems which might degrade overall performance over time. Determining performance problems in sub-assemblies may be very difficult due to their complexity and physical location within the system. Thus there is a need in this art for sophisticated systems and methods for real-time diagnosis of sub-assemblies performance problems by a technician during on-site maintenance.
Accordingly, what is needed in this art are increasingly sophisticated systems and method for detecting and diagnosing real-time performance problems in sub-assemblies driven by a dc motor.